The present invention relates to portable information processing apparatuses, such as a laptop personal computer, to which an expansion unit (an external device) is mountable.
A laptop personal computer (hereinafter called xe2x80x9ca note PCxe2x80x9d), to which functions can be added through an expansion unit, is often battery-powered for outdoor use where the note PC alone is used, and the note PC itself generates little heat.
On the other hand, when the expansion unit is hooked up to the note PC, a plurality of functions are added to the note PC, which is then used as a desktop personal computer. In this case, power supplied to the note PC increases in order to execute the add-on functions, so that a temperature in the note PC rises.
As such, a combination use of the note PC with the expansion unit generates greater amount of heat than a use of the note PC alone. A cooling fan is provided in the note PC to suppress temperature-rise, however, it is difficult to add components more than necessary because the note PC is a portable-oriented apparatus.
Japanese patent application non-examined publication No. H11-238984 discloses a method of preventing temperature-rise in a portable information processing apparatus, i.e., heat generated in the apparatus is conveyed to a fan equipped to an external unit via heat conductive means, so that the fan is activated. This conventional portable apparatus with the external unit disclosed in the foregoing publication is described with reference to FIG. 4.
FIG. 4 shows a lateral view of portable information processing apparatus 40 which includes main body 41 and external device 20. Main body 41 has main unit 31 and lid 32. Main unit 31 is equipped with heat-producing components (not shown) such as semi-conductors, printed circuit boards, rectifiers. Heat generated from those components travels to heat-dissipating bottom plate 34. External device 20 has metallic housing 21 in which cooling mechanism 22, comprising a cooling fan and heat sink, is situated opposite to heat-dissipating bottom plate 34.
In the vicinity of cooling mechanism 22, silicone rubber as heat conductive means is placed, and temperature sensor 23 is also disposed. Pedestal 24 receives main body 41 horizontally.
An operation of the portable information processing apparatus discussed above is described hereinafter. Note PC 40 is connected to the commercial current and the note PC is booted together with the external device. In this status, the semiconductors and other components produce heat, which is conveyed to the vicinity of cooling mechanism 22 (e.g. the fan) via heat dissipating bottom plate 34 and silicone rubber 30.
In due course, temperature sensor 23 detects silicone rubber 30 reaches a given temperature, then temperature control means activates fan 22, which blows air to silicone rubber 30 to cool. This coldness of silicone rubber 30 is transferred to the semiconductors and other components in main unit 31 thereby the semiconductors and other components are cooled.
As such, a cooling fan equipped to an expansion unit allows a note PC to maintain its portability and yet to work a plurality of add-on functions. Recently, note PCs alone are frequently used outdoor, so that the note PCs can be used in versatile conditions, which requires higher reliability in a worse condition. For instance, a note PC alone is desirably dust-proof as well as water proof and yet regulates temperature-rise therein. Further, the note PC carries out add-on functions through an expansion unit, and regulates heat generated from the sophisticated PC. However, in the prior art discussed above, the fan provided for the external device cools the main body indirectly using the heat conductive means such as the silicone rubber. Thus inside of the main body cannot be cooled efficiently.
The present invention addresses the problem discussed above and aims to provide a portable information processing apparatus that can maintain its dust-proof and water-proof capacities and yet regulate heat generated from a note PC using add-on functions through an external device.
The portable information processing apparatus of the present invention comprises the following elements:
a main body; and
an external device to be coupled with the main body externally for providing add-on functions and including a cooling fan that cools parts of a housing of the main body when the external device is coupled with the main body.